### Please describe the problem.
I had a working git-annex repo (simple, one remote full clone on a separate machine) that worked fine with assistant and everything. I added a backblaze S3 special remote and now the assistant gives me an Internal Server Error with the message "S3 bucket not configured". The git annex command line seems to not care about this situation (I can push to the remote, it's enabled, etc etc).

### What steps will reproduce the problem?
I used the command

AWS_ACCESS_KEY_ID=SECRET AWS_SECRET_ACCESS_KEY=SECRET git annex initremote backblaze type=S3 signature=v4 host=s3.us-west-002.backblazeb2.com encryption=shared bucket=annex-calibre protocol=https

to create the special remote. I was pretty proud of myself that I got it first try without messing up.


### What version of git-annex are you using? On what operating system?
xentac@baxter:~/calibre$ git annex version
git-annex version: 10.20240430-1~ndall+1
build flags: Assistant Webapp Pairing Inotify DBus DesktopNotify TorrentParser MagicMime Benchmark Feeds Testsuite S3 WebDAV
dependency versions: aws-0.22.1 bloomfilter-2.0.1.0 cryptonite-0.29 DAV-1.3.4 feed-1.3.2.1 ghc-9.0.2 http-client-0.7.13.1 persistent-sqlite-2.13.1.0 torrent-10000.1.1 uuid-1.3.15 yesod-1.6.2.1
key/value backends: SHA256E SHA256 SHA512E SHA512 SHA224E SHA224 SHA384E SHA384 SHA3_256E SHA3_256 SHA3_512E SHA3_512 SHA3_224E SHA3_224 SHA3_384E SHA3_384 SKEIN256E SKEIN256 SKEIN512E SKEIN512 BLAKE2B256E BLAKE2B256 BLAKE2B512E BLAKE2B512 BLAKE2B160E BLAKE2B160 BLAKE2B224E BLAKE2B224 BLAKE2B384E BLAKE2B384 BLAKE2BP512E BLAKE2BP512 BLAKE2S256E BLAKE2S256 BLAKE2S160E BLAKE2S160 BLAKE2S224E BLAKE2S224 BLAKE2SP256E BLAKE2SP256 BLAKE2SP224E BLAKE2SP224 SHA1E SHA1 MD5E MD5 WORM URL VURL X*
remote types: git gcrypt p2p S3 bup directory rsync web bittorrent webdav adb tahoe glacier ddar git-lfs httpalso borg rclone hook external
operating system: linux x86_64
supported repository versions: 8 9 10
upgrade supported from repository versions: 0 1 2 3 4 5 6 7 8 9 10
local repository version: 10

Running on Ubuntu 24.04 LTS

### Please provide any additional information below.

[[!format sh """
# If you can, paste a complete transcript of the problem occurring here.
# If the problem is with the git-annex assistant, paste in .git/annex/daemon.log

The only relevant daemon.log lines look like this:

ConfigMonitor crashed: S3 bucket not configured

12/Jul/2024:12:47:05 -1000 [Error#yesod-core] S3 bucket not configured @(yesod-core-1.6.24.0-BAaAxHVEp0K8WBRS1ADQQK:Yesod.Core.Class.Yesod src/Yesod/Core/Class/Yesod.hs:705:6)



# End of transcript or log.
"""]]

### Have you had any luck using git-annex before? (Sometimes we get tired of reading bug reports all day and a lil' positive end note does wonders)
I've successfully used git-annex (on and off) since you ran the kickstarter to develop the assistant :) I really like the project.

